/**

 * vim: set ts=4 :

 * =============================================================================

 * SourceMod

 * Copyright (C) 2004-2008 AlliedModders LLC.  All rights reserved.

 * =============================================================================

 *

 * This program is free software; you can redistribute it and/or modify it under

 * the terms of the GNU General Public License, version 3.0, as published by the

 * Free Software Foundation.

 * 

 * This program is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more

 * details.

 *

 * You should have received a copy of the GNU General Public License along with

 * this program.  If not, see <http://www.gnu.org/licenses/>.

 *

 * As a special exception, AlliedModders LLC gives you permission to link the

 * code of this program (as well as its derivative works) to "Half-Life 2," the

 * "Source Engine," the "SourcePawn JIT," and any Game MODs that run on software

 * by the Valve Corporation.  You must obey the GNU General Public License in

 * all respects for all other code used.  Additionally, AlliedModders LLC grants

 * this exception to all derivative works.  AlliedModders LLC defines further

 * exceptions, found in LICENSE.txt (as of this writing, version JULY-31-2007),

 * or <http://www.sourcemod.net/license.php>.

 *

 * Version: $Id$

 */

#include "ThreadWorker.h"

ThreadWorker::ThreadWorker(IThreadWorkerCallbacks *hooks) : BaseWorker(hooks),

	m_Threader(NULL),

	m_QueueLock(NULL),

	m_StateLock(NULL),

	m_PauseSignal(NULL),

	m_AddSignal(NULL),

	me(NULL),

	m_think_time(DEFAULT_THINK_TIME_MS)

{

	m_state = Worker_Invalid;

}

ThreadWorker::ThreadWorker(IThreadWorkerCallbacks *hooks, IThreader *pThreader, unsigned int thinktime) : 

	BaseWorker(hooks),

	m_Threader(pThreader),

	m_QueueLock(NULL),

	m_StateLock(NULL),

	m_PauseSignal(NULL),

	m_AddSignal(NULL),

	me(NULL),

	m_think_time(thinktime)

{

	if (m_Threader)

	{

		m_state = Worker_Stopped;

	} else {

		m_state = Worker_Invalid;

	}

}

ThreadWorker::~ThreadWorker()

{

	if (m_state != Worker_Stopped || m_state != Worker_Invalid)

	{

		Stop(true);

	}

	if (m_ThreadQueue.size())

	{

		Flush(true);

	}

}

void ThreadWorker::OnTerminate(IThreadHandle *pHandle, bool cancel)

{

	//we don't particularly care

	return;

}

void ThreadWorker::RunThread(IThreadHandle *pHandle)

{

	WorkerState this_state = Worker_Running;

	size_t num;

	if (m_pHooks)

	{

		m_pHooks->OnWorkerStart(this);

	}

	while (true)

	{

		/**

		 * Check number of items in the queue

		 */

		m_StateLock->Lock();

		this_state = m_state;

		m_StateLock->Unlock();

		if (this_state != Worker_Stopped)

		{

			m_QueueLock->Lock();

			num = m_ThreadQueue.size();

			if (!num)

			{

				/** 

				 * if none, wait for an item

				 */

				m_Waiting = true;

				m_QueueLock->Unlock();

				/* first check if we should end again */

				if (this_state == Worker_Stopped)

				{

					break;

				}

				m_AddSignal->Wait();

				m_Waiting = false;

			} else {

				m_QueueLock->Unlock();

			}

		}

		m_StateLock->Lock();

		this_state = m_state;

		m_StateLock->Unlock();

		if (this_state != Worker_Running)

		{

			if (this_state == Worker_Paused || this_state == Worker_Stopped)

			{

				//wait until the lock is cleared.

				if (this_state == Worker_Paused)

				{

					m_PauseSignal->Wait();

				}

				if (this_state == Worker_Stopped)

				{

					//if we're supposed to flush cleanrly, 

					// run all of the remaining frames first.

					if (!m_FlushType)

					{

						while (m_ThreadQueue.size())

						{

							RunFrame();

						}

					}

					break;

				}

			}

		}

		/**

		 * Run the frame.

		 */

		RunFrame();

		/**

		 * wait in between threads if specified

		 */

		if (m_think_time)

		{

			m_Threader->ThreadSleep(m_think_time);

		}

	}

	if (m_pHooks)

	{

		m_pHooks->OnWorkerStop(this);

	}

}

SWThreadHandle *ThreadWorker::PopThreadFromQueue()

{

	if (m_state <= Worker_Stopped && !m_QueueLock)

	{

		return NULL;

	}

	SWThreadHandle *swt;

	m_QueueLock->Lock();

	swt = BaseWorker::PopThreadFromQueue();

	m_QueueLock->Unlock();

	return swt;

}

void ThreadWorker::AddThreadToQueue(SWThreadHandle *pHandle)

{

	if (m_state <= Worker_Stopped)

	{

		return;

	}

	m_QueueLock->Lock();

	BaseWorker::AddThreadToQueue(pHandle);

	if (m_Waiting)

	{

		m_AddSignal->Signal();

	}

	m_QueueLock->Unlock();

}

WorkerState ThreadWorker::GetStatus(unsigned int *threads)

{

	WorkerState state;

	m_StateLock->Lock();

	state = BaseWorker::GetStatus(threads);

	m_StateLock->Unlock();

	return state;

}

bool ThreadWorker::Start()

{

	if (m_state == Worker_Invalid)

	{

		if (m_Threader == NULL)

		{

			return false;

		}

	} else if (m_state != Worker_Stopped) {

		return false;

	}

	m_Waiting = false;

	m_QueueLock = m_Threader->MakeMutex();

	m_StateLock = m_Threader->MakeMutex();

	m_PauseSignal = m_Threader->MakeEventSignal();

	m_AddSignal = m_Threader->MakeEventSignal();

	m_state = Worker_Running;

	ThreadParams pt;

	pt.flags = Thread_Default;

	pt.prio = ThreadPrio_Normal;

	me = m_Threader->MakeThread(this, &pt);

	return true;

}

bool ThreadWorker::Stop(bool flush_cancel)

{

	if (m_state == Worker_Invalid || m_state == Worker_Stopped)

	{

		return false;

	}

	WorkerState oldstate;

	//set new state

	m_StateLock->Lock();

	oldstate = m_state;

	m_state = Worker_Stopped;

	m_FlushType = flush_cancel;

	m_StateLock->Unlock();

	if (oldstate == Worker_Paused)

	{

		Unpause();

	} else {

		m_QueueLock->Lock();

		if (m_Waiting)

		{

			m_AddSignal->Signal();

		}

		m_QueueLock->Unlock();

	}

	me->WaitForThread();

	//destroy it

	me->DestroyThis();

	//flush all remaining events

	Flush(true);

	//free mutex locks

	m_QueueLock->DestroyThis();

	m_StateLock->DestroyThis();

	m_PauseSignal->DestroyThis();

	m_AddSignal->DestroyThis();

	//invalidizzle

	m_QueueLock = NULL;

	m_StateLock = NULL;

	m_PauseSignal = NULL;

	m_AddSignal = NULL;

	me = NULL;

	return true;

}

bool ThreadWorker::Pause()

{

	if (m_state != Worker_Running)

	{

		return false;

	}

	m_StateLock->Lock();

	m_state = Worker_Paused;

	m_StateLock->Unlock();

	return true;

}

bool ThreadWorker::Unpause()

{

	if (m_state != Worker_Paused)

	{

		return false;

	}

	m_StateLock->Lock();

	m_state = Worker_Running;

	m_StateLock->Unlock();

	m_PauseSignal->Signal();

	if (m_Waiting)

	{

		m_AddSignal->Signal();

	}

	return true;

}